@article{graham_yoon_lee_kim_2009,  title={Strain and sex differences in fear conditioning: 22 kHz ultrasonic vocalizations and freezing in rats},  volume={2},  ISSN={1983-3288},  url={https://doi.org/10.3922/j.psns.2009.2.015},  DOI={10.3922/j.psns.2009.2.015},  number={2},  journal={Psychology & Neuroscience},  publisher={Pontificia Universidade Católica do Rio de Janeiro, Universidade de Brasília, Universidade de São Paulo},  author={Graham, Lauren K. and Yoon, Taejib and Lee, Hongjoo J. and Kim, Jeansok J.},  year={2009},  month={Jul},  pages={219–225} }